胰腺癌细胞对5-氟尿嘧啶和健择产生获得性耐药的分子生物学机制初探

目的　探索胰腺癌细胞对 5 氟尿嘧啶 ( 5 FU)和健择产生获得性耐药的机制 ,分析这种耐药与凋亡的调控基因———bcl 2家族之间的关系。方法　 5 FU和健择的细胞毒性作用通过磺酰罗丹明B蛋白染色法 (SRB)来检测 ,应用RNA酶保护分析法来检测化疗药物作用前后bcl 2家族mRNA表达水平。结果　 5 FU和健择对 3株胰腺癌细胞均产生了细胞毒性作用 ,5 FU长期作用后 ,Capan 1细胞 5 0 %抑制浓度 (IC50 )上升了 2 .1倍 (P <0 .0 5 )。健择长期作用后 ,Capan 1细胞IC50 上升了 1.8倍 (P <0 .0 5 )。RNA酶保护分析结果提示 ,bcl xL 和mcl 1上调的细胞产生了获得性耐药。结论　化疗药物长期作用后 ,抑凋亡基因bcl xL 和mcl 1上调 ,胰腺癌细胞产生了获得性耐药。阻断这些抑凋亡基因的表达可能提高胰腺癌细胞对 5 FU和健择的敏感性 ,从而产生治疗作用。     

胰腺癌细胞对5氟脲嘧啶和健择的获得性耐药机制的研究

目的探讨胰腺癌细胞对 5氟脲嘧啶 (5 FU)和健择产生获得性耐药的机制。方法用磺酰罗丹明B蛋白染色法检测细胞毒性作用 ,根据药物剂量与细胞生存的关系计算 5 0 %抑制浓度(IC50 ) ;用RNA酶保护分析和Westernblot法来检测Bcl xL和mcl 1的表达水平。结果 5 FU和健择对 3株胰腺癌细胞均产生了细胞毒性作用。 5 FU长期作用后 ,Capan 1细胞IC50 上升了 2 1倍 (P <0 0 5 ) ;健择长期作用后 ,Capan 1细胞IC50 上升了 1 8倍 (P <0 0 5 ) ;而Mia Paca 2细胞在 5 FU和健择作用前后IC50 明显降低 (P <0 0 5 )。产生获得性耐药细胞的Bcl xL 和mcl 1的表达均上调。结论胰腺癌细胞对 5 FU相对耐药 ,而对健择较为敏感。化疗药物长期作用后 ,抑凋亡基因Bcl xL和mcl 1的表达上调 ,胰腺癌细胞产生了获得性耐药。     

胰腺癌细胞对5—Fu和吉西它滨获得性耐药后bcl—XL和mcl—l表达的变化

目的：探讨胰腺癌细胞对5－Fu和吉西它滨的获得性耐药后bcl-XL和mcl-l表达的变化。方法：应用SRB方法检测5－Fu和吉西它滨对胰腺癌细胞株Panc-1,Mia-Paca-2和Capan-1的细胞毒性作用，应用Western blot法来检测bcl-XL和mcl-l的蛋白表达水平。结果：5－Fu和吉西它滨对3株胰腺癌细胞均产生了细胞毒性作用，5－Fu长期作用后，Capan-1细胞IC50上升了2．1倍（P＜0．05）。吉西它滨长期作用后，Capan-1细胞IC50上升了1．5倍（P＜0．05）。5－Fu或吉西它滨长期作用后，产生了获得性耐药的胰腺癌细胞bcl-XL和mcl-1表达水平上调。结论：5－Fu或吉西它滨长期作用后，产生了获得性耐药，这种耐药与bxl-XL和mcl-l的过度表达相关。     

吉西他滨诱导胰腺癌细胞PANC-1中survivin基因表达的研究

目的:探讨吉西他滨诱导胰腺癌细胞PANC-1中survivin表达与化疗耐药的关系。方法:胰腺癌细胞株PANC-1用1640液培养，吉西他滨的浓度为1 μg /mL及10 μg/mL，运用RT-PCR和Western blot检测survivin的表达。分析细胞中survivin的表达水平与化疗耐药的关系。结果:用1 μg/mL及10 μg/mL浓度的吉西他滨作用胰腺癌细胞株24 h和48 h，survivin mRNA水平分别上升了(1.34±0.12) 倍,(2.40±0.17)倍和(3.33±0.20)倍,(4.41±0.18)倍;蛋白水平上升了(1.20±0.07)倍,(1.48±0.19)倍和(2.90±0.04)倍,(4.50±0.20)倍，差异有显著性意义(P＜0.05)。结论:胰腺癌细胞株的化疗耐药可能通过吉西他滨的作用上调survivin的表达而增强。     

大鼠脑损伤后脑神经细胞内bcl-2和bcl-xL水平的变化及意义

目的　观察大鼠急性脑损伤后脑神经细胞内bcl 2、bcl xL的表达状况及意义。　方法55只大鼠采用弥漫性脑损伤模型制成轻、重度 2组大鼠脑损伤模型 ,以免疫组化方法 ,检测脑神经细胞中bcl 2、bcl xL的表达水平 ;以原位细胞凋亡 (TUNEL)法检测神经细胞凋亡水平。　结果　正常大鼠神经细胞中很少有bcl 2表达 (额顶区 4 40± 1 67,海马区 3 2 0± 1 30 ) ;但可见bcl xL表达 (额顶区45 60± 4 34 ,海马区 50 2 0± 3 50 )。大鼠大脑遭受打击后 ,神经细胞bcl 2表达明显增高 ,以伤后第 1天最为明显 (轻度组 :皮层 :30 0± 4 3 ,海马 :46 6± 3 2 ) ,轻度组高于重度组。各观测时间点bcl 2表达水平与神经细胞凋亡水平呈负相关 (r在 - 0 847～ - 1 0 0 0之间 ,P <0 0 1 ,n =1 0 )。bcl xL表达变化不明显。　结论　大鼠急性脑损伤后脑神经细胞内bcl 2表达增高 ,而bcl xL在损伤后变化不大 ,两者可能与急性脑损伤后保护神经细胞避免凋亡有关     

酸性神经磷脂酶及神经酰胺在吉西他滨诱导胰腺癌PANC-1细胞耐药中的作用

目的 建立对吉西他滨耐药的胰腺癌PANC-1/Gem细胞株,检测诱导耐药前后该细胞株生物学特性的变化.探讨吉西他滨诱导胰腺癌耐约的可能机制.方法 通过逐渐增加培养基中吉西他滨的浓度,建屯对吉西他滨耐药的胰腺癌PANC-1/Gem细胞株,TUNEL染色检测细胞株凋亡,MTT方法 检测胰腺癌PANC-1和胰腺癌PANC-1/Gem细胞的半数抑制浓度(IC_(50))和耐药指数(RI),Western印迹法检测酸性神经磷脂酶表达变化、二酰基甘油激酶(diacylglycerol kinase,DAGK)法检测神经酰胺含量变化.结果 经过24周成功诱导出对吉西他滨耐药的胰腺癌PANC-1/Gem细胞株,吉西他滨对PANC-1和PANC-1/Gem细胞的IC_(50)值分别为:亲本(8.13±0.85)μg/ml,24周(285.40±34.83)μg/ml,与亲本细胞相比耐药倍数为35.10倍,且凋亡率降低.Western印迹检测发现吉西他滨诱导24周的胰腺癌细胞PANC-1/Gem酸性神经磷脂酶的表达低于亲本细胞.两组细胞的神经酰胺含量分别为:亲本(364.95±46.11)pmol/mg protein,24周(120.61±20.07)pmol/mgprotein.结论 酸性神经磷脂酶的表达降低,导致神经酰胺含量减少可能是胰腺癌PANC-1细胞株对吉西他滨产生耐药的机制之一.     

汉防己甲素和吉西他滨协同使用对化疗耐药胰腺癌细胞的凋亡诱导作用

目的：研究汉防己甲素对胰腺癌化疗耐药产生与凋亡的影响。方法：分对照组（只加培养基）、吉西他滨组（Gemcitabine组）和汉防己甲素联合吉西他滨组（Tet/Gem组）,后2组采用不同浓度汉防己甲素和吉西他滨作用于人胰腺癌敏感株BxPC-3和吉西他滨耐药株BxPC-3/Gem细胞,通过MTT法检测抗肿瘤药物的细胞毒作用,碘化丙啶（PI）染色检测细胞凋亡。结果：BxPC-3/Gem耐药胰腺癌细胞株耐药指数（RF）为4.70,汉防己甲素作用耐药胰腺癌细胞后其RF降至1.69,证明汉防己甲素可逆转BxPC-3/Gem耐药胰腺癌细胞对吉西他滨的耐药。化疗耐药胰腺癌细胞凋亡在12h、18h、24h,Tet/GEM组与GEM组、对照组比较,差异有非常显著性意义（P〈0.01）。结论：汉防己甲素可以逆转BxPC-3/Gem耐药胰腺癌细胞对吉西他滨的耐药,协同吉西他滨促进对化疗耐药胰腺癌细胞凋亡作用。     

吉西他滨诱导胰腺癌细胞ABCG2表达其化疗耐药的关系研究

目的：探讨吉西他滨诱导胰腺癌细胞ABCG2的表达及与其化疗耐药的关系。 方法：吉西他滨不同浓度、不同时间作用胰腺癌SW1990细胞后,用CCK-8法检测细胞的增殖抑制率,并计算吉西他滨不同作用时间的半数抑制浓度（IC50）;根据IC50值选择合适浓度的吉西他滨,作用SW1990细胞24、48、72 h后,用流式细胞仪检测细胞凋亡率,并用Western blot和RT-PCR法检测ABCG2蛋白与mRNA的表达。 结果：吉西他滨作用后,SW1990细胞增殖明显抑制,并呈浓度与时间依赖性,但IC50值呈时间依赖性增加（均P<0.05）;3.9 mg/mL吉西他滨作用24、48、72 h后,SW1990细胞总凋亡率逐渐增加,但晚期凋亡率呈降低趋势,ABCG2蛋白与mRNA的表达明显升高,并呈时间依赖性（均P<0.05）。 结论：吉西他滨能抑制胰腺癌细胞SW1990的增殖,但作用呈时间依赖性减弱,这可能与其诱导ABCG2上调表达有关。     

丝裂原活化蛋白激酶磷酸酶1与胰腺癌细胞获得性耐药的关系

目的 探讨丝裂原活化蛋白激酶（MAPK）磷酸酶1（MKP-1）在介导胰腺癌耐药细胞株SWl990／Fu产生获得性耐药过程中的可能机制。方法 采用Northern印迹杂交和Western蛋白免疫印迹杂交方法,检测MKP-1在体外诱导建立的人胰腺癌耐药细胞株SWl990／Fu、亲本细胞株SWl990和胰腺癌细胞株MiaPaCa-2中的表达,分析MKP-1在SW1990／Fu产生获得性耐药前后的变化。结果 Northern印迹杂交结果显示,在SWl990／Fu、SWl990和MiaPaCa~细胞株中均检测到2400bp的MKP-1mRNA,MKP-1在SWl990／Fu的表达水平明显低于SWl990和MiaPaCa-2。在蛋白水平上,Western蛋白免疫印迹杂交结果也表明,与SWl990和MiaPaCa4相比,MKP-1蛋白在SWl990／Fu细胞中的表达水平明显降低。结论 MAPK家族的关键调节酶MKP-1可能参与SWl990／Fu获得性耐药的产生,推测细胞信号转导系统的改变可能是导致胰腺癌细胞产生获得性耐药的机制之一。     

DPC4基因转染对胰腺癌细胞化疗敏感性的影响

目的 运用基因转染技术,观察DPC4基因转染对胰腺癌细胞化疗敏感性的影响.方法 构建表达DPC4基因的逆转录病毒载体,转染胰腺癌细胞BxPC-3,获取稳定表达DPC4的子代胰腺癌的细胞株BxPC-3/DPC4.观察5-Fu、吉西他滨(作用72 h)对胰腺癌细胞的抑制作用.同时应用半定量RT-PCR检测胰腺癌细胞内Mdr-1、Chk1基因的表达情况.结果 DPC4基因转染并稳定表达后,BxPC-3细胞对5-Fu、吉西他滨的IC50浓度(72 h)分别降低了1倍左右.同一浓度下,5-Fu、吉西他滨联合DPC4基因转染对BxPC-3细胞的体外抑制作用也明显增强,癌细胞内的Mdr-1、Chk1基因的mRNA表达明显下调.显示单独使用pLXSN/DPC4、5-Fu、吉西他滨,均能在体外抑制胰腺癌细胞的生长,但pLXSN/DPC4联合化疗药物,对癌细胞生长的抑制作用更为明显.结论 DPC4基因转染能够提高胰腺癌细胞对化疗药物的敏感性,其机制可能是通过下调Mdr-1、Chkl的表达来实现的.     

Hedgehog信号通路相关蛋白在人胰腺癌SW1990耐药株中的表达及意义

目的:探讨Hedgehog信号通路蛋白在人胰腺癌吉西他滨耐药细胞株SW1990中的表达,为克服胰腺癌获得性耐药提供实验基础。方法:采用浓度梯度递增法建立人胰腺癌SW1990耐药株,采用噻唑蓝法测定SW1990亲代与耐药细胞IC50。实时荧光定量PCR检测亲代与耐药细胞mRNA中hedgehog信号通路成员Shh、SMO、Gli-1的表达差异。Western印迹法检测亲代与耐药细胞中上述蛋白质的表达。结果:人胰腺癌耐药株SW1990的IC50从亲代的(3.1±0.2)μmol/L提高到(232.2±12.3)μmol/L。荧光定量PCR结果显示耐药株中Shh、Gli-1的表达提高了(12.07±1.71)倍和(4.15±0.42)倍。亲代SW1990中未检测到SMO表达,而耐药细胞中却可以检测到SMO的表达。Western印迹结果同样显示,人胰腺癌SW1990耐药细胞株中高表达上述蛋白质。结论:人胰腺癌耐药株中高表达部分hedgehog信号通路蛋白。针对hedgehog信号通路的靶向治疗可能为克服胰腺癌耐药提供新的理论基础。     

Effect of matrix metalloproteinase inhibition on pancreatic cancer invasion and metastasis: an additive strategy for cancer control

OBJECTIVE: To investigate the effect of a matrix metalloproteinase (MMP) inhibitor, BB-94, on the viability, invasion, and metastases of pancreatic cancer. SUMMARY BACKGROUND DATA: Inhibitors of MMPs, enzymes that degrade extracellular matrix, have been tested as single chemotherapeutic agents for pancreatic cancer. METHODS: Capan1 and AsPC1 cell lines were studied. BB-94 cytotoxicity was evaluated by cell proliferation assays. Production of MMP2 and MMP9 in conditioned media was demonstrated by gelatin zymography. The in vitro effect of BB-94 on cell invasion was assayed using invasion chambers. Hepatic metastases from pancreatic cancer were induced by intrasplenic injections of Capan1 or AsPC1 cells in nude mice. The in vivo effect of BB-94 on liver metastases was evaluated by comparing animals receiving BB-94 treatment with controls receiving vehicle alone. Variables measured included death rate and tumor burden (liver-to-body weight ratio). RESULTS: BB-94 was not cytotoxic between 3 and 3,000 ng/mL. Zymography demonstrated production of MMP2 and MMP9 by both cell lines, with complete inhibition of these enzymes by BB-94 at 48 ng/mL. Invasion chamber assays showed that BB-94 (48-400 ng/mL) impeded cell invasion in vitro compared with untreated controls. In vivo, BB-94 prevented death or reduced the death rate from hepatic metastases in animals injected with Capan1 or AsPC1 cells. BB-94 treatment resulted in significant reductions in hepatic tumor burden compared with untreated controls. CONCLUSIONS: Inhibition of MMP reduces both growth of pancreatic cancer metastases and the death rate. These actions do not reflect cytotoxicity but rather result from impaired cancer cell attachment, migration, and organ invasion. MMP inhibitors may provide an additive effect to cytotoxic agents in multidimensional treatment regimens for pancreatic cancer.     

白细胞介素6促进人胰腺癌细胞的侵袭及机制探讨

目的 应用白细胞介素6(IL-6)作用于人胰腺癌细胞株SW1990和Capan-2,观察侵袭能力的变化并探讨其机制.方法 使用IL-6处理人胰腺癌细胞株SW1990和Capan-2,MTT法检测细胞增殖,免疫细胞化学和Western印迹检测P-STAT3的表达,荧光定量PCR、Western印迹检测VEGF、MMP-2 mRNA和蛋白表达,体外侵袭检测细胞的侵袭能力.结果 IL-6 100 μg/L作用人胰腺癌细胞株后,细胞增殖能力增强(P＜0.05);Western印迹和免疫细胞化学显示P-STAT3的表达增加;荧光定量PCR、Western印迹显示VEGF、MMP-2的mRNA和蛋白表达明显升高(P＜0.05);细胞侵袭能力增强.结论 IL-6通过激活STAT3信号转导通路,上调MMP-2和VEGF表达,增强胰腺癌细胞侵袭能力.

Abstract：

Objective To investigate the effects and mechanism of IL-6 on invasion and metastasis of human pancreatic cancer cells. Methods IL-6 was added into the culture media of human pancreatic cancer cells Capan-2 and SW1990. Cell growth was measured by MTT assay. Western blot and immunocytochemistry were performed to detect Phosphorylated STAT3 (P-STAT3) protein. VEGF and MMP-2 mRNA and protein expression were examined using fluorescence quantitative polymerase chain reaction (RT-PCR) and Western blot, respectively. The invasion ability of SW1990 and Capan2 cells was determined by cell invasion assay in vitro. Results 100 ng/mL IL-6 significantly promoted growth and invasion ability of Capan-2 and SW1990 cells (P＜0.05). The use of IL-6 not only markedly increased the protein expression of P-STAT3, VEGF and MMP-2, but also greatly increased the mRNA expression of MMP-2 and VEGF. Conclusions STAT3 signal transducer pathway activation with IL-6 can promote the invasion ability of pancreatic cancer cells in vitro through up-regulation of MMP-2 and VEGF expression. STAT3 signal transducer may provide a novel therapeutic target for the treatment of pancreatic cancer.     

siRNA directed against c-Src enhances pancreatic adenocarcinoma cell gemcitabine chemosensitivity

BACKGROUND: The c-Src tyrosine kinase is a determinant of malignant cellular behavior in a variety of human cancers. We sought to determine the effect of suppressing c-Src expression on pancreatic adenocarcinoma chemosensitivity to gemcitabine. STUDY DESIGN: PANC1, MIAPaCa2, BxPC3, and Capan2 pancreatic adenocarcinoma cell lines were studied. Expression of c-Src was determined by Western blot analysis. c-Src kinase activity was determined by in vitro kinase assay. RNA interference was used to suppress c-Src expression. Gemcitabine-induced cytotoxicity was determined by tetrazolium reduction assay and caspase profiling was performed. The effect of Src-specific siRNA on Akt activity was quantified. RESULTS: Src expression and kinase activity in cell lines were directly correlated with gemcitabine chemoresistance. c-Src-specific siRNA suppressed c-Src expression and kinase activity. c-Src-specific siRNA increased gemcitabine-induced, caspase-mediated apoptosis. Akt activity was decreased by suppression of c-Src expression. CONCLUSIONS: c-Src is a determinant of pancreatic adenocarcinoma chemoresistance and represents a potential target for therapeutic intervention.     

Effects of the proteasome inhibitor bortezomib on gene expression profiles of pancreatic cancer cells

BACKGROUND: Pancreatic cancer remains a highly chemoresistant malignancy. Gemcitabine is a widely used clinical chemotherapeutic agent against locally advanced and metastatic pancreatic cancer. Proteasome inhibitor bortezomib has been shown to result in enhanced cytotoxicity and apoptosis when used alone or in combination with gemcitabine in pancreatic cancer cell lines. MATERIALS AND METHODS: To determine the effect of bortezomib on gene expression profile of pancreatic adenocarcinoma cells with different sensitivity to gemcitabine, we used Affymetrix HG U133A 2.0 GeneChip (Santa Clara, CA) and measured changes induced by bortezomib in pancreatic cancer cell lines with high (BxPC-3) and low (PANC-1) sensitivity to gemcitabine, at time points 24 h. Selected genes were subsequently validated by quantitative real-time polymerase chain reaction. RESULTS: Forty-four common genes in both PANC-1 and BxPC-3 cells were identified as up-regulated (>3-fold) induced by bortezomib analyzed by microarray, which are associated with multiple cytotoxic and cytoprotective effects. Bcl-2 was repressed by bortezomib in both PANC-1 and BxPC-3 cells, while no changes induced in either cell by bortezomib were disclosed in all five members of nuclear factor-kappa B family. Other interesting genes related to apoptosis or drug metabolism, such as TP53 and ABCB1 (mdr1), were not found differentially expressed in common. CONCLUSIONS: Bortezomib exhibits antitumor effects toward pancreatic cancer in vitro and in vivo. Genes with divergent apoptotic effects are induced by bortezomib, which may become promising targets for pancreatic cancer treatment.     

紫龙金对前列腺癌细胞系DU-145的体外作用

目的　探讨中药紫龙金 (ZLJ)对雄激素非依赖型人前列腺癌细胞系DU 14 5的体外作用及其机制。方法　应用四甲基偶氮唑蓝 (MTT)比色法、软琼脂集落生长试验和流式细胞术测定ZLJ对DU 14 5的增殖抑制、集落生长抑制、周期阻滞和诱导凋亡作用 ,应用逆转录 聚合酶链反应 (RT PCR)和Westernblot方法检测对凋亡相关基因 /蛋白bcl 2和bax ,抑癌基因 /蛋白p16表达的影响。结果　ZLJ具有时间和剂量依赖性增殖抑制、G0 /G1期阻滞和诱导凋亡作用 ,作用 72hIC50 为 0 .42g/L ,ZLJ 0 .1g/L作用 14d对DU 14 5细胞集落生长抑制率为 87.9% ,ZLJ 0 .5 g/L作用 2dG0 /G1期细胞比例从 41.3 0 %增高至 76.70 %。ZLJ可以下调bcl 2基因 /蛋白 ,上调bax和p16基因 /蛋白的表达。 结论　ZLJ可能通过抑制DU 14 5细胞的集落生长、增殖抑制、G0 /G1期阻滞、诱导凋亡、下调bcl 2基因 /蛋白 ,上调bax和 p16基因 /蛋白表达等作用机制发挥抗肿瘤作用。